The present invention relates generally to the field of storing and dispensing pressurized gas. In particular, the present invention relates to a valve assembly for use with a pressurized gas container filling system and a method of filling a pressurized gas container such as a low-pressure gas cylinder.
The term xe2x80x9cgasxe2x80x9d is used herein to describe not only the gaseous state of a substance but also an aerosol and a vapour associated with a liquefied gas.
Gases are conveniently stored and transported in a pressurized state, often in a pressurized gas cylinder. For many domestic (i.e. non-industrial) applications, it is convenient that the pressurized gas cylinder be portable. For example, a scuba diver needs to have a portable supply of breathable gas in order to remain underwater for any length of time and a paramedic needs a portable supply of oxygen for administration to an injured person at the scene of an accident. In addition, DIY welding gases are also stored in portable cylinders as too is carbon dioxide in fire extinguishers.
A further example of a domestic application of pressurized gas is the use of pressurized xe2x80x9clighter-than-airxe2x80x9d gas to fill balloons. Suitable xe2x80x9clighter-than-airxe2x80x9d gases include helium or xe2x80x9cballoon gasxe2x80x9d (predominately helium). Usually, the balloons are referred to as helium-filled balloons.
In recent years, there has been a marked increase in the demand for helium-filled balloons. Such balloons are used for example as party decorations, children""s"" toys or promotional and advertising materials. As a result of this demand, helium-filled balloons are widely available from many different retail outlets. These outlets may specialize in other goods but sell helium-filled balloons as a side-line or may specialize in selling helium-filled balloons, e.g. stand-alone stalls located in shopping malls or high streets.
In addition, some outlets rent cylinders of pressurized balloon gas to the public. A rented cylinder would then be taken to the place where large numbers of helium-filled balloons are required so that the balloons may be filled in situ. In such cases, the cylinders would be transported using a vehicle such as the family car.
Industry also uses cylinders of pressurized gases. For example, where an inert atmosphere is required, the atmosphere could be provided by an unreactive (or xe2x80x9cinertxe2x80x9d) gas, stored in and dispensed from a pressurized gas cylinder. Whilst industrial cylinders tend to hold more gas than domestic cylinders, portable cylinders in general tend to have a small storage capacity and, thus, quickly become empty and need replacing frequently.
One solution to this problem is to provide disposable containers. Gas Container Services Limited of Roadway No. 7, Colwick Industrial Estate, Nottingham, NG4 2JW, United Kingdom provides a helium-filled balloon kit comprising a disposable helium tank under the trade mark BALLOON TIME.
More commonly, portable pressurized gas cylinders are designed to be refillable from a high-pressure gas source. Two options exist in this regard. First, the empty cylinders may be collected and taken to a central filling depot for refilling. The second option is to refill the cylinders at their place of use or sale. In this connection, the process of transferring gas from a high-pressure cylinder to a low-pressure cylinder is known as xe2x80x9ctransfillingxe2x80x9d.
The first option is currently the preferred option for the re-filling of cylinders for industrial use in which the cylinders are transported to the filling depot using a purpose built lorry. Unfortunately, for domestic applications (where the quantity of gas in a single cylinder is less that that for industrial applications resulting in shorter periods between cylinder refills), this approach is less attractive as it requires the transportation of large quantities of cylinders on a frequent basis, which can be expensive and time-consuming.
When a pressurized cylinder is re-filled at the filling depot, the outlet of the cylinder is connected to a filling manifold that is, in turn, connected via a flexible hose to a source of high-pressure gas. In this case, the source of high-pressure gas is a compressor or pump and vaporizer in gas flow communication with a gas source. A valve on the cylinder outlet is opened and the cylinder is charged with gas from the high-pressure gas source to a pre-set pressure by opening a feed valve. On completion, the feed valve is closed first and then the cylinder valve is closed. The filling manifold is then vented using a vent valve and the flexible hose is disconnected. This specific sequence of steps is repeated each time a cylinder is refilled. This is not only time-consuming but also requires specialist training.
A gas flow control device must then be fitted to the outlet of the cylinder before the cylinder is able to dispense gas for its intended application. For example, with cylinders of balloon gas, a regulator and balloon filling attachment must be fastened to the cylinder outlet before the cylinder may be used to fill balloons.
West Winds of 33672 Pin Oak Parkway, Avon Lake, Ohio 44012, USA provides a transfill system that allows high pressure helium gas cylinders to be refilled at retail premises using a flexible hose connected to a supply of higher pressure helium gas. The higher-pressure helium gas supply can take the form of more than one cylinder linked in series. The system uses the same sequence of connections, valve operations and disconnections as used in connection with the depot transfill system described above. Further, a gas flow control unit needs to be connected to a re-filled cylinder before gas can be safely dispensed from the cylinder to fill balloons.
Both of these systems require a specific sequence of steps in order to safely transfill a pressurized gas cylinder from a higher-pressure gas source and specialist training is required. If the valves are not operated in the correct sequence, the receiving cylinder could be under or over-filled or high-pressure gas could be released. Further, the West Winds system is designed to transfill high-pressure cylinders from a source of higher-pressure gas. If a low-pressure cylinder is mistakenly transfilled using the West Winds system, then there is a risk that the cylinder may explode causing injury to the user. In addition, both systems require the removal of a gas flow control unit from the cylinder prior to transfill and the reconnection of a gas flow control unit after the cylinder has been refilled. These extra steps significantly increase the time taken to refill a cylinder ready for use and may require specialist training.
Widget World of Blackpole Trading Estate East, Blackpole Road, Worcester, WR3 8SG, United Kingdom provides a high pressure helium gas cylinder system for filling balloons under the trade mark MIDGET WIDGET. The system comprises a high-pressure helium gas cylinder with a valve that acts to secure the contents of the cylinder and regulates the pressure of the gas within the cylinder. The system has an operating handle, which operates the valve and which acts as a balloon-filling adapter. The handle is transported separately from the cylinder and is fitted by the end-user. The cylinder of this system must be returned to the depot for re-filling as it is charged to high pressure. It is not possible to refill the cylinder at the retail outlet.
There is a need, therefore, for a transfill system that can be used to refill a pressurized gas cylinder in situ, i.e. at the place at which the cylinder is used or sold, rather than having to transport the empty cylinder to a refilling depot. There is also a need to simplify the sequence of steps taken to refill a cylinder so that no specialist training is required and so that the overall length of time taken to fill a cylinder is reduced.
It has been found that these needs have, at least in part, been fulfilled using the present invention. Accordingly, there is provided as a first aspect of the present invention, a valve assembly comprising a first gas flow control unit for controlling the flow of pressurized gas to and from a pressurized container and a second gas flow control unit for controlling the flow of gas from a high pressure gas source to the container, wherein the first control unit comprises:
a first valve housing for mounting said first control unit in gas flow communication with the interior of the container, said housing having a first gas flow path; and
a first valve located in the first gas flow path to open and close said path which, in use, is biased in a closed position;
and wherein the second gas flow control unit comprises:
a second valve housing for mounting said second control unit in gas flow communication with the interior of the high pressure gas source, said housing having a second gas flow path; and
a second valve located in the second gas flow path to open and close said path which, in use, is biased in a closed position;
said assembly further comprising actuating means for co-operatively opening the first and second valves when the first and second control units are brought into compressed engagement, wherein said actuating means comprises a gas flow path located therethrough to provide gas flow communication between said first and second gas flow paths.
The invention provides a transfill system that allows pressurized gas cylinders to be refilled in situ in a safe, efficient and cost effective manner. The present invention is simple to use, requires no mechanical skills and minimal training. In addition, the valve on the cylinder can be used not only to transfill the cylinder but also to dispense gas from the cylinder. The transfill process is simplified, as the valve on the cylinder does not need to be replaced before transfilling. The valve on the cylinder is simply brought into compressed engagement with the valve of the source of high-pressure gas. This reduces the time taken to refill a cylinder and the necessity for tools and specialist training. In this connection, it may be necessary to use a tool to remove a nozzle from the valve of the cylinder before the cylinder may be transfilled. However, tools to remove the valve from the cylinder are not required.
As the transfill process is simplified using the present invention, the risk of an accident resulting from the incorrect application of the transfill sequence of steps is reduced. The present invention also makes it difficult for users to tamper with and/or bypass the protective systems.
The valve assembly of the present invention allows low pressure gas containers, such as cylinders, to be re-filled without having to remove the gas flow control units and without having to use tools to form mechanical joints. In other words, the same gas flow control unit is used to dispense gas from the container as is used to refill the container.
According to a second aspect of the present invention, there is provided apparatus for filling a pressurized gas container comprising:
a second control unit as defined by the first aspect of the present invention;
conduit means for supplying pressurized gas from a pressurized gas source to said second control unit; and
means for providing compressed engagement between said second control unit and co-operating first control unit of the valve assembly as defined by the first aspect of the present invention;
wherein gas enters the container via the conduit means and the valve assembly when the first and second control units are brought into compressed engagement.
According to a third aspect of the present invention, there is provided a pressurized gas cylinder having an outlet in which is mounted a first control unit as defined in the first aspect of the present invention.
According to a fourth aspect of the present invention, there is provided a system for filling pressurized gas cylinders comprising:
apparatus according to the second aspect of the present invention; and
a plurality of pressurized gas cylinders according to the third aspect of the present invention.
According to a fifth aspect of the present invention, there is provided a method of filling a pressurized gas container from a source of high pressure gas comprising;
providing a valve assembly as according to the first aspect of the present invention in gas flow communication with a pressurized gas container and said pressured gas source; and
providing compressed engagement between the first control unit 1 and the second control unit of the valve assembly.